Convert to Cylindrical Coordinates from Cartesian

1st int(-2 to 2), 2nd int(-sqrt(4-x^2) to sqrt (4-x^2)), 3rd int((x^2+y^2) to 4) X dz dy dx.

I changed the integrals to Cylindrical 1st int(0 to pi), 2nd int(-2 to 2), 3rd int(r^2 to 4) and the X to r cos(theta). r dz dr dtheta. I know this is wrong because I keep getting zero for the answer to area.